The present invention is to provide a closure device for a scupper drain and, more particularly a closure device which is normally maintained in a closed position to automatically close a scupper drain onto which the device is mounted. The device is comprised of two semi-circular pivotal flaps which form a swinging door having a size substantially equal to the inner diameter of the associated scupper drain passage. The swinging door is further supported by two springs which retain the door in a normal closed position before or after dirty water is discharged.
In regular water troughs or scuppers, water discharging pipes are normally connected at the bottom. After a certain period of application, debris accumulated inside the scupper to receive flies, cockroaches, reptiles or vermin. The scuppers may become a dead corner in environmental sanitation. At night, reptiles and vermin may come out from the scuppers to seek food, and simultaneously, to promote diseases. It is known to insert a cap to close up the scupper so as to prevent from passing therethrough of reptiles and vermin and also to prevent release of bad odor from the water discharging pipe.
In addition to a regular cover cap for directly covering the scupper, there is also known a kind of weight controlled swinging door used to control the scupper. The cover cap is very inconvenient in use, since it must be picked up for water discharging and reinstalled in the scupper each time after water is discharged.
As shown in FIG. 4, a known weight controlled swinging door includes a pin rod to pivot a swinging door to a scupper with a weight provided at the shorter side of the swinging door so that the swinging door is constantly kept in a normal closed condition.
This kind of weight controlled swinging door still has the following drawbacks.
1. Because the swinging door has a weight attached thereto at one side, during water discharging the side of the swinging door where the weight is connected is projected upward and the other side of the swinging door is pushed downward. If the rushing force of the discharging water is uneven against the swinging door or if there is any miscellaneous objects carried with the dirty water, the upward projecting angle of the swinging door may be forced to exceed an angle of 90.degree., thereby causing the swinging door to be turned upside-down (as shown in FIG. 4-A). PA0 2. In order to prevent the swinging door from turning upside-down, a stopping means must be set above the swinging door. The arrangement of such a stopping means is rather inconvenient and will also reduce the water discharging area of the scupper (as shown in FIG. 4-B). PA0 3. Because a regular filter cap, which is mounted on the top of a scupper, has bigger filter holes, miscellaneous objects tend to follow dirty water running downward from the scupper into the water discharging pipe. In case the miscellaneous objects are detained by the side of the swinging door where the weight is connected, the swinging door may not be able to close (as shown in FIG. 4-c). PA0 4. In order to provide high sensitivity to facilitate water discharging, the weight connected side and the non-weight side of the swinging door are very close in weight. Therefore, reptiles may easily push the weight connected side of the swinging door upward so as to open the swinging door, thereby reducing the effectiveness of the swinging door.
Neither the said cover cap nor the weight controlled swinging door is fully automatic. A user shall have to constantly pick up and insert the cover cap for water discharging or to set the weight controlled swinging door into the correct position each time it is retained by miscellaneous objects and is rendered unable to close the scupper. Furthermore, this device cannot prevent from passing therethrough of reptiles and vermin, thus threatening environmental sanitation and human health.